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I think we're arguing over how many angels can dance on the head of a pin. I mean, the reality is that we have discovered more planets in the last few years, not fewer, and the reluctance to deal with an ever-growing body of planets has led them into a position of obstinacy.

I am going to have to cut my wrists. My existential view of the world had been shattered. The next thing you know they will be saying that Santa Claus and the Easter Bunny do not exist. I am sure that this is George W. Bush’s fault.

It happens that there is a philosopher called Freidrich Hegel, whom I must confess I specifically detest. And I am happy to share that profound feeling with a far greater man [Karl Friedrich] Gauss. In 1800 Hegel presented a thesis, if you please, proving that although the definition of planets had changed since the Ancients, there still could only be, philosophically, seven planets. Well, not only Gauss knew how to answer that: Shakespeare had answered that long before. There is a marvellous passage in King Lear, in which who else but the Fool says to the King: 'The reason why the seuen Starres are no mo then seuen, is a pretty reason'. And the King wags sagely and says: 'Because they are not eight'. And the Fool says: 'Yes indeed, thou woulds't make a good Foole'. And so did Hegel. On 1 January 1801, punctually, before the ink was dry on Hegel's dissertation, an eighth planet was discovered — the minor planet Ceres.

Wasn't there a new planet found in this solar system a couple of years ago? I know I read a long time ago that the Sumerians swore there were 10 planets and that made me wonder how it could be that the Sumerians knew what a planet even was.

The situation as it stands is this. There are 6 classes of objects orbiting the Sun directly. 1) Inner planets, 2) gas giants, 3) Asteroids, 4) outer rock-ice planets, 5) Kuiper Belt objects, 6) Comets. There have been 2 or 3 new planets discovered in category 4 (which includes Pluto) during the last few years, named Sedna and Xena. There is apparently no sharp distinction between classes 4 and 5, thus embarrassing astronomers as there might be an endless stream of new "planets". They decided to draw the line at the gas giants, but this is arbitrary, one could have drawn it at the level of the inner planets or past Sedna somewhere.

The point is that a somewhat arbitrary decision has been made and given the ancient sanction of "planet". Another species in another solar system, faced with the same question, might have made an entirely different choice.